It is a book that makes no compromises for its reader - if you want to follow the book, you're going to have to pay really close attention. Taking notes might be in order, just to follow the cast of characters. Hell, wouldn't hurt just to keep up with what kingdom you're in at any given moment. I can see why this book was recommended to me by tricksterquinn, and I can see why artaxastra recced it to her.
A truly, truly wonderfully dense world Carey has created, though. The depth of detail, especially in things like the marque of the Servants of Naamah, is really amazing. My only complaint is that Carey references, and gives tiny snippets of, poem after poem, but we never get to see the entire work. I'd love to see a book of Kushiel poetry.
So - many thanks for the recs. Gonna take a break to do something mindless, then move on to the next rec.